US7158345B2 - Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same - Google Patents
Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same Download PDFInfo
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- US7158345B2 US7158345B2 US11/016,949 US1694904A US7158345B2 US 7158345 B2 US7158345 B2 US 7158345B2 US 1694904 A US1694904 A US 1694904A US 7158345 B2 US7158345 B2 US 7158345B2
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- core layer
- track width
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
- G11B5/3109—Details
- G11B5/3116—Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
- G11B5/3109—Details
- G11B5/312—Details for reducing flux leakage between the electrical coil layers and the magnetic cores or poles or between the magnetic cores or poles
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
- G11B5/3163—Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
- G11B5/3109—Details
- G11B5/313—Disposition of layers
Definitions
- the present invention relates, generally, to a thin-film magnetic write head such as a floating type magnetic head and more particularly, the invention relates to a thin-film magnetic head in which side fringing can be appropriately suppressed and that can be fabricated with a high degree of consistency, and to a method for fabricating the same.
- FIG. 24 is a partial front view showing the structure of a conventional thin-film magnetic head (inductive head), and FIG. 25 is a partial sectional view of the thin-film magnetic head shown in FIG. 24 .
- insulating layers 3 are formed on both sides of a lower core layer 1 composed of a magnetic material, such as Permalloy.
- a gap layer 4 and an upper pole layer 5 are formed with a track width Tw on the lower core layer 1 , and also are formed so as to be exposed at a surface facing a recording medium.
- Tw track width
- the gap layer 4 extends on the lower core layer 1 to a position at which a base 10 b of an upper core layer 10 , which will be described below, and the lower core layer 1 come into contact with each other, and the upper pole layer 5 extends onto a Gd-setting insulating layer 6 formed on the gap layer 4 .
- the gap layer 4 is composed of a nonmetallic insulating material, such as SiO 2 .
- an insulating layer 7 is formed so as to be disposed on both sides of the upper pole layer 5 in the track width direction (in the X direction in the drawing) and to extend in the height direction (in the Y direction in the drawing).
- a coil layer 13 is spirally patterned, and the coil layer 13 is embedded in an insulating layer 9 composed of an organic insulating material.
- the upper core layer 10 is formed, for example, by frame plating, on the insulating layer 9 , and a tip 10 a of the upper core layer 10 is magnetically coupled to the upper pole layer 5 and also is formed so as to be exposed at the surface facing the recording medium.
- the base 10 b of the upper core layer 10 is magnetically coupled to the lower core layer 1 .
- the entirety of a tip surface 10 c of the upper core layer 10 is formed so as to be exposed at the surface facing the recording medium.
- the gap layer 4 composed of an insulating material, such as SiO 2 , is formed over the entire surface of the lower core layer 1 , and a resist layer 11 having a groove 11 a that is equal to the track width Tw is formed on the gap layer 4 .
- the groove 11 a is formed with a predetermined length from the surface facing the recording medium in the height direction (in the Y direction in the drawing).
- the upper pole layer 5 composed of, for example, an NiFe alloy, is plated in the groove 11 a, and the resist layer 11 is removed.
- the width of the upper pole layer 5 i.e., the track width Tw, is set, for example, at 0.45 ⁇ m, and a height h 1 is set at approximately 3.5 to 3.8 ⁇ m.
- Both sides of the upper pole layer 5 in the track width direction are etched by ion milling (trimming step).
- ion milling trimming step.
- portions of the gap layer 4 exceeding the width of the upper pole layer 5 are trimmed away and also the upper surface of the lower core layer 1 on both sides are trimmed, and thus a protrusion 1 b and inclined planes 1 a are formed on the lower core layer 1 .
- the insulating layer 7 composed of Al 2 O 3 or the like, is formed on the lower core layer 1 on both sides of the upper pole layer 5 so as to embed the upper pole layer 5 in the insulating layer 7 . Then, , as shown in FIG. 30 , the insulating layer 7 is polished at the line A—A using a CMP technique.
- a resist layer 12 is formed over the insulating layers 7 and 9 and the upper pole layer 5 . A portion corresponding to a pattern 12 a of the resist layer 12 is exposed and developed, and the portion corresponding to the pattern 12 a is removed.
- FIG. 32 shows the structure in the vicinity of the tip of the thin-film magnetic head.
- the trimming step described above and shown in FIG. 27 is usually carried out twice.
- ion irradiation is performed substantially perpendicular to the plane direction of the lower core layer 1 .
- the gap layer 4 extending on both sides of the lower surface of the upper pole layer 5 is trimmed, and portions of the lower core layer 1 under the gap layer 4 are also trimmed, and thus the protrusion 1 b of the lower core layer 1 is formed.
- ion irradiation is performed in more inclined directions in comparison with the first trimming step so that the magnetic dust is removed and the inclined planes 1 a are formed on the lower core layer 1 on both sides of the protrusion 1 b.
- the trimming step is carried out, and in the trimming step, variations in the track width Tw and in the shape occur, and also the height of the upper pole layer 5 is significantly decreased.
- the reason for carrying out the trimming step is that in the state shown in FIG. 27 , since the gap layer 4 and the lower core layer 1 extend on both sides of the lower surface of the upper pole layer 5 , side fringing easily occurs between the upper pole layer 5 and the lower core layer 1 .
- FIG. 28 by trimming the gap layer 4 extending on both sides of the lower surface of the upper pole layer 5 and by further forming the protrusion 1 b and the inclined planes 1 a, the distance between the upper pole layer 5 and the lower core layer 1 can be increased, and thus the side fringing is believed to be appropriately suppressed.
- the trimming step is carried out, the uniformity during the fabrication of thin-film magnetic heads is reduced, and due to the decrease in the height of the upper pole layer 5 , the volume of the upper pole layer 5 is decreased.
- the upper pole layer 5 is easily magnetically saturated, resulting in degradation in recording characteristics.
- objects of the present invention are to provide a thin-film magnetic head in which side fringing can be appropriately suppressed and which can be fabricated with a high degree of consistency, and to provide a method for fabricating the same.
- a thin-film magnetic head includes a lower core layer; a recording core formed on the lower core layer and exposed at a face surface facing a recording medium, in which a lower pole layer, a gap layer, and an upper pole layer are deposited in that order, or in which a gap layer and an upper pole layer are sequentially deposited in that order; an upper core layer magnetically coupled to the upper pole layer; and a coil for inducing a recording magnetic field to the lower core layer, the recording core, and the upper core layer.
- a tip surface of the upper core layer at the face surface is set back from the face surface in a direction generally perpendicular to the face surface, which is referred to hereinafter as the height direction.
- the tip surface is an inclined surface or a curved surface in which the depth gradually increases in a direction generally parallel to the face surface, which hereinafter is referred to as the track width direction.
- the tip surface of the upper core layer is set back from the face surface in the height direction, and also the tip surface is an inclined surface or a curved surface in which the depth gradually increases in the track width direction, the tip surface of the upper core layer is not exposed, in contrast to the conventional case. Consequently, in the present invention, it is possible to appropriately suppress side fringing, and simultaneously, the flux from the upper core layer can be efficiently applied to the upper pole layer, and thus it is possible to fabricate a thin-film magnetic head which is suitable for an increased recording density.
- the shortest setback distance L 3 from the face surface to the tip surface of the upper core layer is equal to or less than the largest length of the recording core from the face surface in the height direction Furthermore, the setback distance L 3 preferably satisfies the relationship about 0 ⁇ m ⁇ L 3 ⁇ about 0.8 ⁇ m.
- the upper core layer is provided with a back surface which is set back from the tip surface in the height direction, the back surface is a curved surface or an inclined surface in which the depth gradually increases in the track width direction, and an inclination angle ⁇ 2 is greater than an inclination angle ⁇ 1 , where angle ⁇ 1 is one of the inclination angles of the inclined surface relative to the height direction, or the inclination angle of a tangent at a midpoint between an end of the curved surface near the recording core and an end of the curved surface at an upper surface of the upper core layer, and inclination angle ⁇ 2 is the inclination angle of the tip surface of the upper core layer relative to the height direction, or the inclination angle of a tangent line at the midpoint between an end of the curved surface near the recording core and an end of the curved surface on an upper core layer.
- the inclination angle ⁇ 2 satisfies the relationship about 60° ⁇ 2 ⁇ about 90°.
- the flux from the upper core layer can be efficiently applied to the upper pole layer, and thus recording characteristics can be improved.
- the tip surface of the upper core layer at the face surface has a curvature which gradually recedes in the height direction toward both sides in the track width direction. In such a structure, it is possible to suppress side fringing.
- the tip surface of the upper core layer has a curvature, when the upper core layer is patterned on the upper pole layer, even if the upper core layer is slightly deviated from the predetermined position relative to the upper pole layer, it is possible to reduce the side fringing in comparison with the conventional thin-film magnetic head.
- the inclination of the tangent line relative to the track width direction is about 30° to about 60°.
- the upper core layer includes a front region which extends from the tip surface in the height direction and has a uniform width in the track width direction; and a back region which extends from a side opposite the front region in the height direction and in which the width in the track width direction gradually increases in the height direction.
- the upper core layer includes a front region which extends from the curved end at the tip surface in the height direction and has a uniform width in the track width direction; and a back region which extends from a side opposite the front region in the height direction and in which the width in the track width direction gradually increases in the height direction.
- the width of the upper core layer in the track width direction is greater than the width of the upper pole layer in the track width direction.
- the flux from the upper core layer can be efficiently applied to the upper pole layer, and thus recording characteristics can be improved.
- the recording core includes a front region which extends from the face surface in the height direction and has a uniform width in the track width direction; and a back region which extends from the front region in the height direction and in which the width in the track width direction gradually increases in the height direction. If the recording core is provided with such a back region having a large track width Tw, it is possible to increase the contact area between the recording core and the upper core layer.
- the upper core layer overlaps at least the back region of the recording core.
- the gap layer is preferably composed of a nonmagnetic metallic material, and the nonmagnetic metallic material is preferably at least one material selected from the group consisting of NIP, NiPd, NiW, NiMo, Au, Pt, Rh, Pd, Ru, and Cr.
- a method for fabricating a thin-film magnetic head includes the step of:
- a) forming a recording core on a lower core layer comprising one of (1) a lower pole layer, a gap layer, and an upper pole layer sequentially deposited in that order on the lower core layer, wherein a width of the lower pole layer and the upper pole layer in a track width direction, wherein the track width direction is generally parallel to the face surface is determined at the face surface or (2) a gap layer and an upper pole layer sequentially deposited in that order on the lower core layer, wherein a width of the upper pole layer in the track width direction is determined at the face surface;
- step (b) forming an insulating layer at a periphery of the recording core at one of before or after step (a), and making an upper surface of the recording core and an upper surface substantially level with each other;
- step (d) the tip surface of the core layer pattern at the face surface gradually recedes in the height direction toward each of two side surfaces that are spaced apart in the track width direction, and wherein in step (e), the upper core layer is formed so that the tip surface has a curvature.
- the gap layer is preferably composed of a nonmagnetic metallic material for plating, and the nonmagnetic metallic material is preferably at least one material selected from the group consisting of NiP, NiPd, NiW, NiMo, Au, Pt, Rh, Pd, Ru, and Cr.
- the tip surface of the patterned upper core layer is an inclined surface or a curved surface in which the depth gradually increases in the track width direction.
- FIG. 1 is a partial front view of a thin-film magnetic head in accordance with an embodiment of the present invention
- FIG. 2 is a partial cross-sectional view taken along the line II—II of FIG. 1 ;
- FIG. 3 is a partial plan view of the thin-film magnetic head shown in FIGS. 1 and 2 ;
- FIG. 4 is a partial plan view showing another shape of the thin-film magnetic head shown in FIGS. 1 and 2 ;
- FIG. 5 is a partial plan view showing another shape of the thin-film magnetic head shown in FIGS. 1 and 2 ;
- FIG. 6 is a partial plan view showing another shape of the thin-film magnetic head shown in FIGS. 1 and 2 ;
- FIG. 7 is a partial front view of a thin-film magnetic head in accordance with another embodiment of the present invention.
- FIG. 8 is a partial cross-sectional view taken along the line VIII—VIII of FIG. 7 ;
- FIG. 9 is a partial plan view of the thin-film magnetic head shown in FIGS. 7 and 8 ;
- FIG. 10 is a partial plan view showing another shape of the thin-film magnetic head shown in FIGS. 7 and 8 ;
- FIG. 11 is a partial front view of a thin-film magnetic head in accordance with another embodiment of the present invention.
- FIG. 12 is a partial sectional view taken along the line XII—XII of FIG. 11 ;
- FIG. 13 is a partial plan view of the thin-film magnetic head shown in FIGS. 11 and 12 ;
- FIG. 14 is a partial plan view showing another shape of the thin-film magnetic head shown in FIGS. 11 and 12 ;
- FIGS. 15A and 15B are a partial front view and a partial sectional view, respectively, showing a step in accordance with a method for fabricating a thin-film magnetic head of the present invention
- FIGS. 16A and 16B are a partial front view and a partial sectional view, respectively, showing a step in accordance with the invention carried out subsequent to the step shown in FIGS. 15A and 15B ;
- FIGS. 17A and 17B are a partial front view and a partial sectional view, respectively, showing a step in accordance with the invention carried out subsequent to the step shown in FIGS. 16A and 16B ;
- FIGS. 18A and 18B are a partial front view and a partial sectional view, respectively, showing a step in accordance with the invention carried out subsequent to the step shown in FIGS. 17A and 17B ;
- FIG. 19 is a partial plan view showing a step in accordance with the invention carried out subsequent to the step shown in FIGS. 18A and 18B ;
- FIG. 20 is a partial sectional view showing a step in accordance with the invention carried out subsequent to the step shown in FIG. 19 ;
- FIG. 21 is a partial sectional view showing a step in accordance with the invention carried out subsequent to the step shown in FIG. 20 ;
- FIG. 22 is a partial sectional view showing another step in accordance with the invention carried out subsequent to the step shown in FIG. 19 ;
- FIG. 23 is a partial sectional view showing a step in accordance with the invention carried out subsequent to the step shown in FIG. 22 ;
- FIG. 24 is a partial front view of a conventional thin-film magnetic head
- FIG. 25 is a partial sectional view of the thin-film magnetic head shown in FIG. 24 ;
- FIG. 26 is a partial front view showing a step in a method for fabricating a conventional thin-film magnetic head
- FIG. 27 is a partial front view showing a step carried out subsequent to the step shown in FIG. 26 ;
- FIG. 28 is a partial front view showing a step carried out subsequent to the step shown in FIG. 27 ;
- FIG. 29 is a partial front view showing a step carried out subsequent to the step shown in FIG. 28 ;
- FIG. 30 is a partial front view showing a step carried out subsequent to the step shown in FIG. 29 ;
- FIG. 31 is a partial plan view showing a step carried out subsequent to the step shown in FIG. 30 ;
- FIG. 32 is a partial sectional view showing a step carried out subsequent to the step shown in FIG. 31 .
- FIG. 1 is a partial front view of a thin-film magnetic head in accordance with an embodiment of the present invention
- FIG. 2 is a partial sectional view taken along the line II—II of FIG. 1
- FIGS. 3 and 4 are partial plan views of examples of thin-film magnetic heads of the present invention.
- a thin-film magnetic head shown in FIG. 1 is an inductive write head
- a read head using a magnetoresistive effect (MR head) may be deposited on the lower surface of the inductive head.
- a lower core layer 20 shown in FIGS. 1 and 2 is composed of a magnetic material, such as Permalloy. Additionally, when a read head is deposited on the lower surface of the lower core layer 20 , a shielding layer for protecting a magnetoresistive element from noise may be provided. Alternatively, without providing the shielding layer, the lower core layer 20 may be also used as an upper shielding layer of the read head.
- insulating layers 23 are formed on both sides of the lower core layer 20 .
- An upper surface 20 a extending from the base of a lower pole layer 21 which will be described below, may be parallel to the track width direction (the X direction in the drawing), or inclined planes 20 b which incline toward a direction opposite to an upper core layer 26 may be formed.
- the inclined planes 20 b By forming the inclined planes 20 b in the upper surface of the lower core layer 20 , side fringing can be suppressed more appropriately.
- a recording core 24 is formed on the lower core layer 20 so as to be exposed at a surface facing a recording medium.
- the recording core 24 is formed with a track width Tw, (i.e., the recording core 24 is a track-width-defining section).
- the track width Tw is preferably about 0.7 ⁇ m or less, and more preferably about 0.5 ⁇ m or less.
- the recording core 24 has a layered structure including three layers: the lower pole layer 21 , a gap layer 22 , and an upper pole layer 35 .
- the pole layers 21 and 35 and the gap layer 22 will be described below.
- the lower pole layer 21 which is the lowest layer of the recording core 24 , is formed by plating on the lower core layer 20 .
- the lower pole layer 21 is magnetically coupled to the lower core layer 20 , and the material for the lower pole layer 21 may be the same as or be different from that for the lower core layer 20 .
- the lower pole layer 21 may be composed of either a single-layered film or a multi-layered film.
- the height of the lower pole layer 21 is set, for example, at approximately 0.3 ⁇ m.
- the gap layer 22 which is nonmagnetic, is deposited on the lower pole layer 21 . In the present invention, preferably, the gap layer 22 is composed of a nonmagnetic metallic material and is formed by plating on the lower pole layer 21 .
- the nonmagnetic metallic material is preferably at least one material selected from the group consisting of NiP, NiPd, NiW, NiMo, NiRh, Au, Pt, Rh, Pd, Ru, and Cr, and the gap layer 22 may be composed of either a single-layered film or a multi-layered film.
- the height of the gap layer 22 is set, for example, at approximately 0.2 ⁇ m.
- the upper pole layer 35 which is magnetically coupled to the upper core layer 26 , is formed by plating on the gap layer 22 .
- the material for the upper pole layer 35 may be the same as or be different from-that for the upper core layer 26 .
- the height of the upper pole layer 35 is set, for example, at about 2.4 to about 2.7 ⁇ m.
- the recording core 24 is not limited to the layered structure including three layers.
- the recording core 24 may have a layered structure including two layers, the example, the gap layer 22 and the upper pole layer 35 .
- the materials for the lower pole layer 21 and the upper pole layer 35 constituting the recording core 24 may be the same as or different from those for the core layers to which the pole layers are magnetically coupled.
- the lower pole layer 21 and the upper pole layer 35 preferably have higher saturation magnetic flux densities than those of the corresponding lower and upper core layers to which the pole layers are magnetically coupled. If the lower pole layer 21 and the upper pole layer 35 have high saturation magnetic flux densities, it is possible to concentrate the recording magnetic field in the vicinity of the gap, thus improving the recording density.
- a plating underlayer 25 is formed between the lower pole layer 21 and the lower core layer 20 .
- the recording core 24 is formed with a length L 1 from the surface facing the recording medium (ABS) in the height direction (in the Y direction in the drawing).
- a Gd-setting insulating layer 27 composed of a resist or the like is formed on the plating underlayer 25 , and the Gd-setting insulating layer 27 has, for example, a curved surface. As shown in FIG. 2 , the upper pole layer 35 extends over the curvature.
- the height h 2 of the upper pole layer 35 on the Gd-setting insulating layer 27 is set, for example, at approximately 1.4 ⁇ m to 1.7 ⁇ m.
- the height of the upper pole layer thereof was smaller than the height h 2 , and it was not possible to increase the volume of the upper pole layer.
- the height h 2 of the upper pole layer 35 can be increased and the volume of the upper pole layer 35 can be increased. The reason for this is that, as will be disclosed in a fabrication method described below, trimming performed perpendicular to the plane of the lower core layer 20 is not required.
- the length L 1 of the upper pole layer 35 can be increased, and thus the volume of the upper pole layer 35 can be further increased. Therefore, even when the recording density is increased, the magnetic saturation of the upper pole layer 35 can be reduced, and recording characteristics can be improved.
- the gap depth Gd is set at a predetermined length.
- the gap depth Gd is defined by the position of the Gd-setting insulating layer 27 formed on the lower core layer 20 .
- a coil layer 29 is spirally patterned over the lower core layer 20 at the back of the recording core 24 in the height direction (in the Y direction in the drawing) with an insulating underlayer 28 and the plating underlayer 25 therebetween.
- the insulating underlayer 28 is preferably composed of at least one insulating material selected from the group consisting of AlO, Al 2 O 3 , SiO 2 , Ta 2 O 5 , TiO, AlN, AlSiN, TiN, SiN, Si 3 N 4 , NiO, WO, WO 3 , BN, CrN, and SiON.
- the spaces between individual conducting sections of the coil layer 29 are filled by an insulating layer 30 .
- the insulating layer 30 is preferably composed of at least one insulating material selected from the group consisting of AlO, Al 2 O 3 , SiO 2 , Ta 2 O 5 , TiO, AlN, AlSiN, TiN, SiN, Si 3 N 4 , NiO, WO, WO 3 , BN, CrN, and SiON.
- the insulating layer 30 is formed on each side in the track width direction (in the X direction) of the recording core 24 , and the insulating layer 30 is exposed at the surface facing the recording medium.
- an insulating layer 31 composed of an organic insulating material, such as a resist or a polyamide, is formed on the insulating layer 30 , and a second coil layer 33 is spirally patterned on the insulating layer 31 .
- the second coil layer 33 is covered by an insulating layer 32 composed of an organic material, such as a resist or a polyamide, and the upper core layer 26 , which is preferably composed of an NiFe alloy or the like, is patterned, for example, by frame plating, on the insulating layer 32 .
- a tip 26 a of the upper core layer 26 is magnetically coupled to the upper pole layer 35
- a base 26 b of the upper core layer 26 is magnetically coupled to an elevating layer 36 composed of a magnetic material, such as an NiFe alloy, which is formed on the lower core layer 20 .
- the elevating layer 36 may not be provided, and in such a case, the base 26 b of the upper core layer 26 is directly connected to the lower core layer 20 through the plating layer 25 .
- the coil may be single-layered.
- the space at the back of the recording core 24 in the height direction on the lower core layer 20 is filled by the insulating layer 30 , and the coil layer is formed on the insulating layer 30 .
- the second coil layer 33 shown in FIG. 2 is not formed, and the upper core layer 26 is formed over the insulating layer 31 .
- a tip surface 26 c of the upper core layer 26 is not exposed at the surface facing the recording medium, and is set back from the surface facing the recording medium in the height direction (in the Y direction in the drawing).
- the tip surface 26 c of the upper core layer 26 by setting the tip surface 26 c of the upper core layer 26 back from the surface facing the recording medium in the height direction, it is possible to appropriately suppress side fringing.
- the width T 1 in the track width direction (in the X direction) of the tip surface 26 c of the upper core layer 26 is greater than the track width Tw. Consequently, if the tip surface 26 c of the upper core layer 26 is exposed at the surface facing the recording medium, side fringing easily occurs due to flux leakage, and it is not possible to fabricate a thin-film magnetic head which is suitable for an increased recording density. Accordingly, in the present invention, as described above, the tip surface 26 c of the upper core layer 26 is set back in the height direction from the surface facing the recording medium so as to prevent the tip surface 26 c from being exposed at the surface facing the recording medium. Consequently, it is possible to appropriately avoid side fringing between the upper pole layer 35 , which is exposed at the surface facing the recording medium, and the upper core layer 26 , and a thin-film magnetic head which is suitable for an increased recording density can be fabricated.
- the shortest setback distance L 3 from the surface facing the recording medium to the tip surface 26 c of the upper core layer 26 is equal to or less than the largest length (L 1 ) of the recording core from the surface facing the recording medium in the height direction, and the setback distance L 3 preferably satisfies the relationship about 0 ⁇ m ⁇ L 3 ⁇ about 0.8 ⁇ m.
- the tip surface 26 c of the upper core layer 26 is an inclined surface in which the depth in the height direction (in the Y direction) gradually increases from the lower core layer side to the upper core layer side (in the Z direction).
- the tip surface 26 c may be a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side.
- the inclination angle ⁇ 2 of the tip surface 26 c relative to the height direction (the Y direction), or when the tip surface 26 c is a curved surface, the inclination angle ⁇ 2 of the tangent at the midpoint between the end of the 15 curved surface on the lower core layer side and the end of the curved surface on the upper core layer side is set at less than 90°.
- the advantage of setting the inclination angle ⁇ 2 at less than 90° is in that the upper core layer 26 is covered by a protective layer 34 composed of an insulating material, such as Al 2 O 3 , and by setting the inclination angle ⁇ 2 at less than 90°, it is possible to completely fill the space B between the tip 26 a of the upper core layer 26 and the surface facing the recording medium by the protective layer 34 .
- the inclination angle ⁇ 2 is preferably less than 90°, there is a further limitation described as follows.
- the upper core layer 26 is provided with a back surface 26 d at the back of the tip surface 26 c, and the back surface 26 d is an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side.
- the inclination ⁇ 2 is greater than an inclination angle ⁇ 1 , where angle ⁇ 1 is the inclination angle of the inclined surface relative to the height direction or the inclination angle of the tangent at the midpoint between the end of the curved surface on the lower core layer side and the end of the curved surface on the upper core layer side relative to the height direction.
- the inclination angle ⁇ 2 more preferably, satisfies the relationship about 60° ⁇ 2 ⁇ about 90°. If the inclination angle ⁇ 2 is less than about 60°, the tapering of the tip 26 a of the upper core layer 26 increases and the volume of the tip 26 a decreases, and thus the transfer efficiency of flux flowing from the upper core layer 26 to the upper pole layer 35 is easily decreased. Additionally, when the tip surface 26 c is a curved surface in which the depth gradually increases from the lower core layer side to the upper core layer side, the curved surface may be either convex or concave.
- the tip surface 26 c of the upper core layer 26 has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- tip surface 26 c of the upper core layer 26 is curved relative to the track width direction instead of being planar as in the conventional case, angles are eliminated between side faces and the tip surface 26 c, and thus flux leakage between the upper core layer 26 and the upper pole layer 35 can be further decreased, and side fringing can be further suppressed.
- the tip surface 26 c of the upper core layer 26 has a curvature relative to the track width direction, even if the position of the upper core layer 26 to be formed on the upper pole layer 35 is slightly deviated in the track width direction (in the X direction) on the upper pole layer 35 , it is possible to reduce the influence of side fringing in comparison with the case in which the tip surface 26 c is planar relative to the track width direction. Therefore, it is possible to fabricate a thin-film magnetic head in which side fringing can be appropriately suppressed even if the alignment accuracy of the upper core layer 26 to the upper pole layer 35 is slightly decreased.
- the inclination angle ⁇ 4 of the phantom line E relative to the track width direction (the X direction) is about 30° to about 60°.
- the upper core layer 26 extends in the height direction from the end 26 e of the curved tip surface 26 c and includes a front region F in which the width in the track width direction is uniform and a back region G in which the width in the track width direction gradually increases from the end on the height side of the front region F in the height direction (in the Y direction in the drawing).
- the present invention is not limited to this shape.
- the front region F may be formed so that the width increases in the height direction along the phantom line E.
- the tip 26 a of the upper core layer 26 is set back from the surface facing the recording medium in the height direction (in the Y direction), and the tip surface 26 c of the upper core layer 26 is an inclined surface or a curved surface in which the depth gradually increases from the lower core layer side to the upper core layer side (in the Z direction in the drawing), and also the tip surface 26 c has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- the width of the upper core layer 26 at the edge in which the upper core layer 26 is connected to the upper pole layer 35 is greater than the width in the track width direction of the upper pole layer 35 . Consequently, it is possible to efficiently apply the flux from the upper core layer 26 to the upper pole layer 35 , and thus recording characteristics can be improved.
- the width in the track width direction of the upper core layer 26 is approximately 2 to 2.5 times the width in the track width direction of the recording core 24 .
- the recording core 24 (formed of three layers consisting of the lower pole layer 21 , the gap layer 22 , and the upper pole layer 35 , or formed of two layers consisting of the gap layer 22 and the upper pole layer 35 ), includes a front region C, which extends from the surface facing the recording medium in the height direction (in the Y direction in the drawing) with the track width Tw, and a back region D in which the width in the track width direction gradually increases from the end on the height side of the front region C in the height direction.
- the recording core 24 is provided with the back region D in which the width is greater than the track width Tw, it is possible to increase the contact area with the upper core layer 26 , and the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 . Consequently, preferably, the upper core layer 26 formed on the recording core 24 is connected to at least the back region D of the recording core 24 , and thus the contact area between the upper core layer 26 and the recording core 24 can be increased.
- the length L 4 of the front region C which is formed with the track width Tw, satisfies the relationship about 0.2 ⁇ m ⁇ L 4 ⁇ about 3.0 ⁇ m. If the length L 4 is below the above range, since the length of the front region C of the recording core 24 becomes too short, it is difficult to define the width of the recording core 24 , which is exposed at the surface facing the recording medium, at the predetermined track width Tw.
- the upper core layer 26 does not easily overlap the back region D of the upper pole layer 35 , and since the overlap between the upper core layer 26 and the front region C of the upper pole layer 35 increases, it is not possible to exploit the advantage that the contact area between the upper core layer 26 and the upper pole layer 35 is increased.
- FIG. 4 is a partial plan view showing another shape of the thin-film magnetic head in accordance with the present invention.
- the recording core 24 is formed with the track width Tw and with a predetermined length L 5 from the surface facing the recording medium in the height direction (in the Y direction in the drawing). That is, in the example shown in FIG. 4 , the back region D in which the width is greater than the track width Tw, as is the case in the example shown in FIG. 3 , is not formed.
- the length L 5 of the recording core 24 is preferably set so as to satisfy the relationship about 0.8 ⁇ m ⁇ L 5 ⁇ about 6.0 ⁇ m.
- the length L 5 is about 0.8 ⁇ m or more, since the contact area between the upper core layer 26 and the upper pole layer 35 is sufficiently large, the transfer efficiency of flux flowing from the upper core layer 26 to the upper pole layer 35 is not decreased.
- the length L 5 is greater than about 6.0 ⁇ m, when the recording core 24 is grown by plating, it is not possible to uniformly form the individual layers, and the thickness may taper at the interior end, or the layers may be curved, resulting in an increase in variations in the magnetic gap and the gap depth Gd, which is disadvantageous.
- the width in the track width direction of the upper core layer 26 at the edge in which the upper core layer 26 is connected to the upper pole layer 35 is greater than the width in the track width direction of the upper pole layer 35 . Consequently, the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 .
- the overlapping ratio between the upper core layer 26 and the recording core 24 and the shape of the upper core layer 26 are the same as those in the example shown in FIG. 3 .
- FIGS. 5 and 6 are partial plan views showing other examples of thin-film magnetic heads in accordance with the present invention.
- a thin-film magnetic head shown in FIG. 5 in the same manner as that in the thin-film magnetic head shown in FIG. 3 , an upper core layer 26 is set back from a surface facing a recording medium in the height direction (in the Y direction in the drawing), and a tip surface 26 c of the upper core layer 26 is not exposed at the surface facing the recording medium.
- a protective layer 34 as shown in FIG. 2 is filled in a space between the surface facing the recording medium and the tip surface 26 c of the upper core layer 26 .
- the tip surface 26 c is an inclined surface or a curved surface in which the depth in the height direction (in the Y direction) gradually increases from the lower core layer side to the upper core layer side.
- the upper core layer 26 By setting the upper core layer 26 back from the surface facing the recording medium in the height direction and by forming the tip surface 26 c into an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side, it is possible to appropriately suppress side fringing between the upper core layer 26 and an upper pole layer 35 , and the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 , and also the space between the tip surface 26 c of the upper core layer 26 and the surface facing the recording medium can be completely filled with the protective layer 34 without a cavity.
- the tip surface 26 c does not have a curvature which gradually recedes in the height direction toward both sides in the track width direction as in the embodiments illustrated in FIGS. 3 or 4 , and the tip surface 26 c has a planar shape which extends parallel to the track width direction (the X direction).
- the tip surface 26 c of the upper core layer 26 has the planar shape in the track width direction, since the tip surface 26 c is set back from the surface facing the recording medium in the height direction (in the Y direction in the drawing), the tip surface 26 c is not exposed at the surface facing the recording medium, thus providing a structure which is effective in suppressing side fringing. Additionally, in the example shown in FIG. 5 , the shape of a recording core 24 formed under the upper core layer 26 has the same shape as that of the recording core 24 shown in FIG. 3 .
- the recording core 24 includes a front region C which extends from the surface facing the recording medium in the height direction (in the Y direction) with the track width Tw, and a back region D in which the width in the track width direction gradually increases from the end on the height side of the front region C in the height direction. Since the recording core 24 is provided with the back region D in which the width gradually increases from the track width Tw, it is possible to increase the contact area between the upper pole layer 35 and the upper core layer 26 .
- the width in the track width direction of the upper core layer 26 at the edge in which the upper core layer 26 is connected to the upper pole layer 35 is greater than the width in the track width direction of the upper pole layer 35 , the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 , thus improving the recording characteristics.
- an upper core layer 26 is set back from a surface facing a recording medium in the height direction, and also a tip surface 26 c of the upper core layer 26 is an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side.
- the-tip surface 26 c of the upper core layer 26 has a planar shape parallel to the track width direction, since the tip surface 26 c is set back from the surface facing the recording medium in the height direction, it is possible to reduce side fringing in comparison with the conventional case.
- a recording core 24 is formed with a track width and with a predetermined length L 5 from the surface facing the recording medium in the height direction.
- the width of the recording core 24 is set to be the track width Tw as described above, the track width Tw is easily defined within a predetermined size.
- the width in the track width direction of the upper core layer 26 at the edge in which the upper core layer 26 is connected to the upper pole layer 35 is greater than the width in the track width direction of the upper pole layer 35 . Consequently, the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 , thus improving the recording characteristics.
- the upper core layer 26 includes a front region F with a uniform width and a back region G in which the width in the track width direction gradually increases from the end on the height side of the front region F in the height direction.
- the present invention is not limited to this shape.
- the front region F may be formed so that the width gradually increases in the height direction.
- FIG. 7 is a partial front view of a thin-film magnetic head in another embodiment of the present invention
- FIG. 8 is a partial cross-sectional view taken along the line VIII—VIII of FIG. 7
- FIGS. 9 and 10 are partial plan views of examples of thin-film magnetic heads.
- a recording core 24 which extends from a surface facing a recording medium in the height direction with a predetermined length L 1 , is formed on a lower core layer 20 , and the recording core 24 is a three-layered film including a lower pole layer 21 , a gap layer 22 , and an upper pole layer 35 , or is a two-layered film including a gap layer 22 and an upper pole layer 35 .
- a Gd-setting insulating layer 27 is formed between the lower core layer 20 and the recording core 24 , and the length L 2 from the surface facing the recording medium to the front surface of the Gd-setting insulating layer 27 is defined as a gap depth (Gd).
- a coil layer 29 is spirally patterned over the lower core layer 20 at the back of the recording core 24 in the height direction with the plating layer 25 and an insulating underlayer 28 therebetween.
- the spaces between individual conducting sections of the coil layer 29 are filled with an insulating layer 30 composed of an inorganic insulating material or the like, and the insulating layer 30 is exposed at the surface facing the recording medium as shown in FIG. 7 .
- An insulating layer 31 composed of an organic insulating material or the like is formed on the coil layer 29 , and a second coil layer 33 is spirally patterned on the insulating layer 31 .
- the second coil layer 33 is covered by an insulating layer 32 composed of an organic insulating material or the like, and an upper core layer 26 is patterned on the insulating layer 32 , for example, by frame plating.
- a tip 26 a of the upper core layer 26 overlies the upper pole layer 35 , and the upper core layer 26 and the upper pole layer 35 are magnetically coupled to each other.
- a base 26 b of the upper core layer 26 is magnetically coupled to an elevating layer 36 composed of a magnetic material formed on the lower core layer 20 .
- the upper core layer 26 is not set back from the surface facing the recording medium in the height direction in contrast to the embodiments shown in FIGS. 1 to 6 .
- a tip surface 26 c of the upper core layer 26 extends to the surface facing the recording medium, and a portion thereof is positioned at the surface facing the recording medium.
- the tip surface 26 c is an inclined surface or a curved surface in which the depth in the height direction (in the Y direction in the drawing) gradually increases from the lower core layer side to the upper core layer side (in the Z direction in the drawing).
- a back surface 26 d located at the back of the tip surface 26 c is an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side.
- an inclination angle ⁇ 2 is greater than an inclination angle ⁇ 1 , where angle ⁇ 1 is the inclination of the back surface 26 d relative to the height direction (or the inclination of the tangent at the midpoint between the end of the curved surface on the lower core layer side and the end of the curved surface on the upper core layer side relative to the height direction), and angle ⁇ 2 is the inclination of the tip surface 26 c relative to the height direction.
- the inclination angle ⁇ 2 of the tip surface 26 c greater than the inclination angle ⁇ 1 of the back surface 26 d as described above, it is possible to prevent the tip 26 a of the upper core layer 26 from tapering, the volume of the tip 26 a can be effectively increased, and the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 , thus improving the recording characteristics.
- the inclination angle ⁇ 2 of the tip surface 26 c satisfies the relationship about 60° ⁇ 2 ⁇ about 90°. If the inclination angle ⁇ 2 is less than about 60°, the tip 26 a of the upper core layer 26 is easily tapered and the volume of the tip 26 a decreases, and thus the transfer efficiency of flux flowing from the upper core layer 26 to the upper pole layer 35 is easily decreased.
- the tip surface 26 c is an inclined surface or a curved surface in which the depth in the height direction (in the Y direction) gradually increases from the lower core layer side to the upper core layer side, in combination with the curvature in the track width direction (in the X direction) of the tip surface 26 c, which will be described below, it is possible to appropriately suppress side fringing.
- the tip surface 26 c of the upper core layer 26 has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- the tip surface 26 c of the upper core layer 26 has the curvature which gradually recedes in the height direction toward both sides in the track width direction, only a portion 26 h of the tip surface 26 c of the upper core layer 26 is exposed at the surface facing the recording medium as shown in FIG. 7 . That is, by forming the tip surface 26 c of the upper core layer 26 so as to have a curvature which gradually recedes in the height direction toward both sides in the track width direction and so as to be an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side, only a slight portion of the tip surface 26 c of the upper core layer 26 is exposed at the surface facing the recording medium.
- the portion 26 h of the tip surface 26 c, which is exposed at the surface facing the recording medium preferably has a width that is less than the track width Tw. Thereby, side fringing can be more appropriately suppressed.
- the tip surface 26 c of the upper core layer 26 has a curvature in the track width direction (in the X direction), even if the position of the upper core layer 26 to be formed on the upper pole layer 35 is slightly deviated in the track width direction (in the X direction) on the upper pole layer 35 , it is possible to reduce the influence of side fringing in comparison with the case in which the tip surface 26 c has a planar shape relative to the track width direction. Therefore, it is possible to fabricate a thin-film magnetic head in which side fringing can be appropriately suppressed even if the alignment accuracy of the upper core layer 26 to the upper pole layer 35 is slightly decreased.
- the inclination angle ⁇ 4 of the phantom line E relative to the track width direction (the X direction) is about 30° to about 60°.
- the tip surface 26 c of the upper core layer 26 is an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side, and also the tip surface 26 c has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- the shape of the recording core 24 formed under the upper core layer 26 shown in FIG. 9 is different from the shape of the recording core 24 shown in FIG. 10 .
- the recording core 24 includes a front region C, which extends from the surface facing the recording medium in the height direction with the track width Tw, and a back region D, in which the width in the track width direction gradually increases from the end on the height side of the front region C in the height direction.
- the recording core 24 extends from the surface facing the recording medium in the height direction with a predetermined length L 5 with the track width Tw, and a back region D is not provided.
- the track width Tw becomes greater than the predetermined size if the length LA of the front region C, which is formed with the track width Tw, is too short, it is possible to increase the contact area between the recording core 24 and the upper core layer 26 due to the presence of the back region D.
- the contact area with the upper core layer 26 is decreased in comparison with the example shown in FIG. 9 , the track width Tw is easily defined within the predetermined size.
- the length L 4 of the front region C in the recording core 24 shown in FIG. 9 preferably satisfies the relationship about 0.2 ⁇ m ⁇ L 4 ⁇ about 3.0 ⁇ m.
- the length L 5 of the recording core 24 shown in FIG. 10 preferably satisfies the relationship about 0.8 ⁇ m ⁇ L 5 ⁇ about 6.0 ⁇ m. The reason for this is as described above.
- the width in the track width direction of the upper core layer 26 at the edge in which the upper core layer 26 is connected to the upper pole layer 35 is greater than the width in the track width direction of the upper pole layer 35 . Consequently, the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 .
- the width in the track width direction of the upper core layer 26 is approximately 2 to 2.5 times the width in the track width direction of the recording core 24 . The reason for this is as described above.
- the upper core layer 26 includes a front region F which extends from the surface facing the recording medium in the height direction (in the Y direction) with a predetermined width, and a back region G in which the width in the track width direction gradually increases from the end on the height side of the front region F in the height direction.
- the present invention is not limited to this shape.
- the front region F may be formed so that the width gradually increases along the phantom line E.
- FIG. 11 is a partial front view of a thin-film magnetic head in accordance with another embodiment of the present invention.
- FIG. 12 is a partial cross-sectional view taken along the line XII—XII of FIG. 11
- FIGS. 13 and 14 are partial plan views of examples of thin-film magnetic heads.
- the shapes of upper core layers 26 are different from the shapes of the upper core layers 26 in the thin-film magnetic heads shown in FIGS. 1 to 6 , sections other than those are the same.
- a recording core 24 which extends from a surface facing a recording medium in the height direction with a predetermined length L 1 , is formed on a lower core layer 20 , and the recording core 24 is a three-layered film including a lower pole layer 21 , a gap layer 22 , and an upper pole layer 35 deposited in that order from the bottom, or is a two-layered film including the gap layer 22 and the upper pole layer 35 .
- a Gd-setting insulating layer 27 is formed between the lower core layer 20 and the recording core 24 , and the length L 2 from the surface facing the recording medium to the front surface of the Gd-setting insulating layer 27 is defined as a gap depth (Gd).
- a coil layer 29 is spirally patterned over the lower core layer 20 at the back of the recording core 24 in the height direction with the plating layer 25 and an insulating underlayer 28 therebetween.
- the spaces between individual conducting sections of the coil layer 29 are filled with an insulating layer 30 composed of an inorganic insulating material or the like, and the insulating layer 30 is exposed at the surface facing the recording medium as shown in FIG. 11 .
- inclined planes 20 b may be formed in the upper surface of the lower core layer 20 . Thereby, side fringing can be suppressed more appropriately.
- An insulating layer 31 composed of an organic insulating material or the like is formed on the coil layer 29 , and a second coil layer 33 is spirally patterned on the insulating layer 31 .
- the second coil layer 33 is covered by an insulating layer 32 composed of an organic insulating material or the like, and an upper core layer 26 is patterned on the insulating layer 32 , for example, by frame plating.
- a tip 26 a of the upper core layer 26 overlies the upper pole layer 35 , and the upper core layer 26 and the upper pole layer 35 are magnetically coupled to each other.
- a base 26 b of the upper core layer 26 is magnetically coupled to an elevating layer 36 composed of a magnetic material formed on the lower core layer 20 .
- the upper core layer 26 is not set back from the surface facing the recording medium in the height direction in contrast to the embodiments shown in FIGS. 1 to 6 .
- a tip surface 26 c of the upper core layer 26 extends to the surface facing the recording medium, and a portion thereof is positioned at the surface facing the recording medium.
- the tip surface 26 c has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- the tip surface 26 c is not an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side in contrast to the embodiments shown in FIGS. 1 to 6 and the embodiments shown in FIGS. 7 to 10 , and the tip surface 26 c is formed parallel to the surface facing the recording medium. Consequently, as shown in FIG. 11 , a portion 26 i, which has a uniform width from the side of the lower core layer to the side of the upper core layer, of the tip surface 26 c of the upper core layer 26 is exposed at the surface facing the recording medium.
- the portion 26 i is the only portion exposed at the surface facing the recording medium.
- the tip surface 26 c of the upper core layer 26 is slightly exposed at the surface facing the recording medium. Consequently, it is possible to reduce flux leakage between the upper core layer 26 and the upper pole layer 35 , and side fringing can be further reduced.
- the portion 26 i of the tip surface 26 c which is exposed at the surface facing the recording medium preferably has a width that is less than the track width Tw. Thereby, side fringing can be more appropriately suppressed.
- the tip surface 26 c of the upper core layer 26 has a curvature in the track width direction, even if the position of the upper core layer 26 to be formed on the upper pole layer 35 is slightly deviated in the track width direction (in the X direction) on the upper pole layer 35 , it is possible to reduce the influence of side fringing in comparison with the case in which the tip surface 26 c has a planar shape relative to the track width direction. Therefore, it is possible to fabricate a thin-film magnetic head in which side fringing can be appropriately suppressed even if the alignment accuracy of the upper core layer 26 to the upper pole layer 35 is slightly decreased.
- the inclination angle ⁇ 4 of the phantom line E relative to the track width direction (the X direction) is about 30° to about 60°.
- the tip surface 26 c has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- the tip surface 26 c is not an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side in contrast to the embodiments shown in FIGS. 1 to 6 and the embodiments shown in FIGS. 7 to 10 .
- the shape of the recording core 24 formed under the upper core layer 26 shown in FIG. 13 is different from the shape of the recording core 24 shown in FIG. 14 .
- the recording core 24 includes a front region C, which extends from the surface facing the, recording medium in the height direction with the track width Tw, and a back region D, in which the width in the track width direction gradually increases from the end edge on the height side of the front region C in the height direction.
- the recording core 24 extends from the surface facing the recording medium in the height direction with a predetermined length L 5 with the track width Tw, and a back region D is not provided.
- the track width Tw becomes greater than the predetermined size if the length L 4 of the front region C, which is formed with the track width Tw, is too short, it is possible to increase the contact area between the recording core 24 and the upper core layer 26 due to the presence of the back region D.
- the shape of the recording core 24 shown in FIG. 14 although the contact area with the upper core layer 26 is decreased in comparison with the example shown in FIG. 13 , the track width Tw is easily defined within the predetermined size.
- the length L 4 of the front region C in the recording core 24 shown in FIG. 13 preferably satisfies the relationship about 0.2 ⁇ m ⁇ L 4 ⁇ about 3.0 ⁇ m.
- the length L 5 of the recording core 24 shown in FIG. 14 preferably satisfies the relationship about 0.8 ⁇ m ⁇ L 5 ⁇ about 6.0 ⁇ m. The reason for this is as described above.
- the width in the track width direction of the upper core layer 26 at the edge in which the upper core layer 26 is connected to the upper pole layer 35 is greater than the width in the track width direction of the upper pole layer 35 . Consequently, the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 .
- the width in the track width direction of the upper core layer 26 is approximately 2 to 2.5 times the width in the track width direction of the recording core 24 . The reason for this is as described above.
- the upper core layer 26 includes a front region F that extends from the surface facing the recording medium in the height direction with a predetermined width, and a back region G, in which the width in the track width direction gradually increases from the end edge on the height side of the front region F in the height direction.
- the present invention is not limited to this shape.
- the front region F may be formed so that the width gradually increases along the phantom line E.
- the thin-film magnetic heads of the present invention it is possible to suppress the side fringing in comparison with the conventional case, the flux from the upper core layer 26 can be efficiently applied to the upper pole layer 35 , and thus it is possible to fabricate a thin-film magnetic head which is suitable for an increased recording density.
- FIGS. 15A and 15B to FIG. 21 shows the steps for fabricating thin-film magnetic heads shown in FIGS. 1 to 4 .
- FIGS. 15A , 16 A, 17 A, and 18 A are partial front views and FIGS. 15B , 16 B, 17 B, and 18 B are corresponding partial cross-sectional views.
- a Gd-setting insulating layer 27 is formed on a lower core layer 20 as shown in FIG. 15B , and then a resist layer 40 with a height h 3 is formed on the lower core layer 20 .
- the height h 3 is set, for example, at approximately 4.0 ⁇ m.
- a groove 40 a is formed in the resist layer 40 by exposure and development with a predetermined length L 6 from a surface facing a recording medium in the height direction.
- the width t 2 of the groove 40 a is set, for example, at approximately 0.45 ⁇ m. Additionally, since the width t 2 is defined as the track width Tw, the width t 2 is preferably set to be as small as possible, for example, at the threshold value of the i-line which is used for exposure.
- a lower pole layer 21 , a gap layer 22 , and an upper pole layer 35 are deposited in that order from the bottom in the groove 40 a by continuous plating.
- the gap layer 22 must be formed using a nonmagnetic metallic material for plating.
- the nonmagnetic metallic material is preferably at least one material selected from the group consisting of NiP, NiPd, NiW, NiMo, Au, Pt, Rh, Pd, Ru, and Cr.
- the three-layered film formed in the groove 40 a constitutes a recording core 24 .
- the recording core 24 is not limited to the three-layered film.
- the recording core 24 may consist of the gap layer 22 and the upper pole layer 35 .
- FIGS. 16A and 16B show a stage in which the resist layer 40 has been removed.
- the width of the recording core 24 formed on the lower core layer 20 is defined as the track width Tw, and the track width Tw is preferably about 0.7 ⁇ m or less, and more preferably about 0.5 ⁇ m or less.
- the height h 4 of the recording core 24 preferably satisfies the relationship about 1 ⁇ m ⁇ h 4 ⁇ about 4 ⁇ m.
- the lower pole layer 21 has a height of approximately about 0.3 ⁇ m
- the gap layer 22 has a height of approximately about 0.2 ⁇ m
- the upper pole layer 35 has a height of approximately about 3.0 to about 3.3 ⁇ m.
- an insulating layer 30 is formed on the lower core layer 20 so as to cover the recording core 24 .
- the insulating layer 30 is preferably composed of an inorganic insulating material.
- the inorganic insulating material is preferably at least one insulating material selected from the group consisting of AlO, Al 2 O 3 , SiO 2 , Ta 2 O 5 , TiO, AlN, AlSiN, TiN, SiN, Si 3 N 4 , NiO, WO, WO 3 , BN, CrN, and SiON.
- the insulating layer 30 is polished using the CMP technique at the line H—H. Thereby, the surface of the insulating layer 30 is planarized, and the surface of the upper pole layer 35 is exposed from the insulating layer 30 .
- FIGS. 18A and 18B insulating layer 30 and recording core 24 after polishing.
- the recording core 24 Since the surface of the recording core 24 is polished by the CMP technique in the step shown in FIGS. 17A and 17B , the recording core 24 has a height h 5 as shown in FIG. 18A , and the height h 5 is set, for example, at approximately 2.4 to 2.7 ⁇ m. As shown in FIG. 18B , the upper pole layer 35 on the Gd-setting insulating layer 27 has a height h 6 , and the height h 6 is set at approximately 1.4 to 1.7 ⁇ m.
- the height h 5 of the recording core 24 and the height h 6 of the upper pole layer 35 on the Gd-setting insulating layer 27 are easily set within the predetermined sizes, and thus it is possible to fabricate a thin-film magnetic head with a high degree of consistency This is because of the fact that a step of trimming substantially perpendicular to the plane of the lower core layer 20 is not carried out.
- the trimming step was necessary in order to suppress side fringing.
- a significant decrease in the height of the upper pole layer 35 and variations in the track width Tw occurred.
- the degree of consistency during fabrication was significantly decreased.
- the gap layer 22 constituting the recording core 24 by forming the gap layer 22 constituting the recording core 24 with a nonmagnetic metallic material for plating, it is possible to continuously form the lower pole layer 21 , the gap layer 22 , and the upper pole layer 35 in that order from the bottom by plating in the groove 40 a of the resist layer 40 shown in FIG. 15A .
- the lower pole layer 21 which protrudes from the lower core layer 20 with the track width Tw, and the gap layer 22 to be formed thereon with the track width Tw can be formed without performing trimming perpendicular to the plane of the lower core layer 20 , and therefore it is possible to fabricate the thin-film magnetic head in which side fringing does not easily occur between the upper pole layer 35 and the lower core layer 20 without carrying out the trimming step.
- trimming may be performed in the step shown in FIGS. 16A and 16B .
- ion irradiation is performed in inclined directions relative to the plane of the lower core layer 20 , and the angle of ion irradiation is set, preferably, at about 45° to about 75° relative to the perpendicular direction to the plane, and more preferably, at about 60° to about 75°.
- the track width Tw of the recording core 24 can be further decreased by the trimming step described above, and it is possible to fabricate a thin-film magnetic head which is suitable for a decreased track width.
- FIG. 19 is a partial plan view of the thin-film magnetic head.
- a pattern 41 a for forming an upper core layer 26 is formed in the resist layer 41 .
- a tip surface 41 b of the pattern 41 a is set back from the face surface in the height direction (in the Y direction in the drawing), and the tip surface 41 b also has a curvature which gradually recedes in the height direction toward both sides 41 c in the track width direction.
- the pattern 41 a in order to form the pattern 41 a, in the present invention, during exposure, a portion 41 d of the resist layer 41 other than the pattern 41 a is irradiated with light, and the exposed resist layer 41 d is developed, and the resist layer 41 corresponding to the pattern 41 a is removed, leaving the resist layer 41 d (image reverse process).
- the exposure and development described above are the reverse of the conventional method. Conventionally, a portion corresponding to the pattern 41 a was irradiated with light.
- the resist layer 41 d other than the pattern 41 a is irradiated with light and developed, and the pattern 41 a, which is not irradiated with light, is removed, due to the shape of the resist layer 41 d.
- FIG. 20 is a partial cross-sectional view of the thin-film magnetic head in the present invention that shows only the shape of tip area of the thin-film magnetic head.
- the resist layer 41 d remains on the insulating layer 30 and the upper pole layer 35 .
- a back surface 41 d 2 thereof is an inclined surface or a curved surface which inclines or curves in the height direction (in the Y direction) from the lower core layer side to the upper core layer side (in the Z direction).
- the resist layer 41 d 1 remains in the shape as described above because light is applied to the resist layer 41 d which is left by the exposure and development.
- the resist layer 41 d 1 remains with the back surface 41 d 2 being an inclined surface or a curved surface which inclines or curves in the opposite direction to the height direction (the Y direction) from the lower core layer side to the upper core layer side.
- the back surface 41 d 2 of the resist layer 41 d 1 is an inclined surface or a curved surface, which inclines or curves in the height direction from the lower core layer side to the upper core layer side, it is possible to form a tip surface 26 c of the upper core layer 26 into an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side by plating a magnetic material for constituting the upper core layer 26 in the pattern 41 a.
- the back surface 41 d 2 of the remaining resist layer 41 d 1 is an inclined surface or a curved surface which inclines or curves in the opposite direction to the height direction (the Y direction) from the lower core layer side to the upper core layer side
- the tip surface 26 c of the upper core layer 26 is formed into an inclined surface or a curved surface which inclines or curves in the direction opposite to the height direction from the lower core layer side to the upper core layer side.
- the resist layer 41 d other than the pattern 41 a for the upper core layer 26 is irradiated with light, followed by development.
- the tip surface of the pattern 41 a to be removed is formed into an inclined surface or a curved surface, which inclines or curves in the height direction from the lower core layer side to the upper core layer side, so that the tip surface 26 c of the upper core layer 26 is an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side.
- the method which has been described with reference to FIGS. 15A and 15B to FIG. 21 relates to a thin-film magnetic head in which the upper core layer 26 is set back from the surface facing the recording medium in the height direction, and the tip surface 26 c of the upper core layer 26 is an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side. Also, the tip surface 26 c has a curvature that gradually recedes in the height direction toward both sides in the track width direction.
- a method for fabricating a thin-film magnetic head in another embodiment will be described below.
- the upper core layer 26 is set back from the surface facing the recording medium in the height direction (in the Y direction), and the tip surface 26 c of the upper core layer 26 is an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side.
- the tip surface 26 c does not have a curvature in the track width direction (in the X direction) and the tip surface 26 c has a planar shape in the track width direction.
- the tip surface of the pattern to be removed is formed into an inclined surface or a curved surface that recedes in the height direction from the lower core layer side to the upper core layer side, and the tip surface is set back from the surface facing the recording medium in the height direction.
- the tip surface 26 c of the upper core layer 26 is positioned at the surface facing the recording medium, and the tip surface 26 c is an inclined surface or a curved surface in which the depth in the height direction gradually increases from the lower core layer side to the upper core layer side, and also the tip surface 26 c has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- the tip surface of the pattern to be removed is formed into an inclined surface or a curved surface that recedes in the height direction from the side of the lower core layer to the side of the upper core layer, and the tip surface is set at the same position as that of the surface facing the recording medium.
- the tip surface 26 c of the upper core layer 26 is positioned at the surface facing the recording medium, and the tip surface 26 c has a curvature which gradually recedes in the height direction toward both sides in the track width direction.
- the tip surface 26 c is not an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side, and the tip surface 26 c is parallel to the surface facing the recording medium.
- the same pattern as that of the upper core layer 26 shown in FIG. 13 or 14 is formed in the resist layer 41 by exposure and development.
- the portion corresponding to the pattern may be irradiated with light or the portion other than the pattern may be irradiated with light.
- the tip surface 26 c is not an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side, when the exposure and development are performed, light may be applied either to the pattern corresponding to the upper core layer 26 or the portion other than the pattern.
- the upper core layer 26 After the pattern for the upper core layer 26 is formed by the exposure and development, by plating a magnetic material for constituting the upper core layer 26 in the pattern, the upper core layer 26 having the shape shown in FIG. 13 or 14 is formed.
- the recording core 24 which is a three-layered film consisting of the lower pole layer 21 , the gap layer 22 , and the upper pole layer 35 or a two-layered film consisting of the gap layer 22 and the upper pole layer 35 , for defining the track width Tw can be formed by continuous plating. Consequently, a trimming step in which ions are irradiated substantially perpendicular to the plane of the lower core layer 20 , as is the case in the conventional method, is not required, and thus it is possible to fabricate a thin-film magnetic head with a high degree of consistency.
- the resist layer for forming the upper core layer 26 can be formed so that the tip surface of the pattern is an inclined surface or a curved surface that recedes in the height direction from the lower core layer side to the upper core layer side by applying light to the portion of the resist layer other than the portion corresponding to the pattern. Consequently, it is possible to form the tip surface 26 c of the upper core layer 26 so that the depth in the height direction increases from the lower core layer side to the upper core layer side.
- the recording core 24 is formed first on the lower core layer 20 and the insulating layer 30 is then formed so as to cover the recording core 24 as shown in FIGS. 15A and 15B to FIGS. 18A and 18B
- the present invention is not limited thereto.
- the insulating layer 30 may be formed first on the lower core layer 20 and a groove is formed in the insulating layer 30 , and then the recording core 24 is formed in the groove.
- the tip surface of the upper core layer by setting back the tip surface of the upper core layer from the surface facing the recording medium in the height direction, and also by setting the tip surface to be an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side, it is possible to suppress side fringing. It is also possible to efficiently apply the flux from the upper core layer to the upper pole layer. Thus, it is possible to fabricate a thin-film magnetic head that is suitable for an increased recording density.
- the tip surface of the upper core layer has a curvature which gradually recedes in the height direction toward both sides in the track width direction, and thus it is possible to suppress side fringing.
- a thin-film magnetic head for suppressing side fringing without a trimming step in which ion irradiation is performed substantially perpendicular to the lower core layer.
- thin-film magnetic heads can be fabricated with a high degree of consistency
- the resist layer for forming the upper core layer is exposed and developed, by applying light to the portion of the resist layer other than the portion corresponding to the pattern for the upper core layer, it is possible to easily form an inclined surface or a curved surface in which the depth in the height direction increases from the lower core layer side to the upper core layer side.
Abstract
Description
Claims (9)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/016,949 US7158345B2 (en) | 2000-03-09 | 2004-12-20 | Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000065288A JP3854031B2 (en) | 2000-03-09 | 2000-03-09 | Thin film magnetic head and manufacturing method thereof |
JP2000-065288 | 2000-03-09 | ||
US09/802,314 US7167340B2 (en) | 2000-03-09 | 2001-03-08 | Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same |
JP2002-321186 | 2002-11-05 | ||
US11/016,949 US7158345B2 (en) | 2000-03-09 | 2004-12-20 | Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US09/802,314 Continuation US7167340B2 (en) | 2000-03-09 | 2001-03-08 | Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same |
Publications (2)
Publication Number | Publication Date |
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US20050168870A1 US20050168870A1 (en) | 2005-08-04 |
US7158345B2 true US7158345B2 (en) | 2007-01-02 |
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Application Number | Title | Priority Date | Filing Date |
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US09/802,314 Expired - Fee Related US7167340B2 (en) | 2000-03-09 | 2001-03-08 | Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same |
US11/016,949 Expired - Fee Related US7158345B2 (en) | 2000-03-09 | 2004-12-20 | Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same |
Family Applications Before (1)
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US09/802,314 Expired - Fee Related US7167340B2 (en) | 2000-03-09 | 2001-03-08 | Thin-film magnetic head appropriately suppressing side fringing and method for fabricating the same |
Country Status (3)
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US (2) | US7167340B2 (en) |
JP (1) | JP3854031B2 (en) |
KR (1) | KR100415446B1 (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7037421B2 (en) * | 2000-05-19 | 2006-05-02 | Alps Electric Co., Ltd. | Thin-film magnetic head having magnetic gap formed of NiP |
JP4079427B2 (en) | 2003-05-14 | 2008-04-23 | Tdk株式会社 | Thin film magnetic head and manufacturing method thereof, head gimbal assembly, and hard disk drive |
US7110217B2 (en) * | 2003-10-15 | 2006-09-19 | Hitachi Global Storage Technologies | Write head design with improved bump to control write saturation |
US7551394B2 (en) * | 2006-07-12 | 2009-06-23 | Headway Technologies, Inc. | Magnetic head for perpendicular magnetic recording having a multilayer shield structure and method of manufacturing same |
US7965464B2 (en) * | 2008-11-20 | 2011-06-21 | Seagate Technology Llc | Heat-assisted magnetic recording with shaped magnetic and thermal fields |
US9934794B1 (en) * | 2016-02-09 | 2018-04-03 | Western Digital (Fremont), Llc | Writer having a recessed trailing shield and nonmagnetic refill |
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Also Published As
Publication number | Publication date |
---|---|
US20040095676A1 (en) | 2004-05-20 |
US20050168870A1 (en) | 2005-08-04 |
KR100415446B1 (en) | 2004-01-24 |
JP2001256611A (en) | 2001-09-21 |
KR20010089244A (en) | 2001-09-29 |
JP3854031B2 (en) | 2006-12-06 |
US7167340B2 (en) | 2007-01-23 |
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